namespace Sirius.Collections
{
    using System;
    using System.Collections.Generic;

    public interface ILookup<TKey, TValue> : IEnumerable<IEnumerable<TValue>>, IEquatable<ILookup<TKey, TValue>>
    {
        bool Contains(TKey key);
        int Count { get; }
        IEnumerable<TValue> this[TKey key] { get; }
    }
}